Steam Deck Client Beta Update: Perf Overlay Fixes

Note: This update is for the Steam Deck Beta and Preview channels, and includes new features that are still being tested. You can opt into this in Settings > System > Steam Update Channel.

General:

• Fixed a case where the Performance Overlay would still show when set to off.
  
• Don't show the "switch to desktop" option in the power menu when the lock screen is active.